projects/linux·blob v4.3 · refs

224 lines · 5.6 KiB

1/*
2 * driver.c - centralized device driver management
3 *
4 * Copyright (c) 2002-3 Patrick Mochel
5 * Copyright (c) 2002-3 Open Source Development Labs
6 * Copyright (c) 2007 Greg Kroah-Hartman <[email protected]>
7 * Copyright (c) 2007 Novell Inc.
8 *
9 * This file is released under the GPLv2
10 *
11 */
12
13#include <linux/device.h>
14#include <linux/module.h>
15#include <linux/errno.h>
16#include <linux/slab.h>
17#include <linux/string.h>
18#include <linux/sysfs.h>
19#include "base.h"
20
21static struct device *next_device(struct klist_iter *i)
22{
23 struct klist_node *n = klist_next(i);
24 struct device *dev = NULL;
25 struct device_private *dev_prv;
26
27 if (n) {
28 dev_prv = to_device_private_driver(n);
29 dev = dev_prv->device;
30 }
31 return dev;
32}
33
34/**
35 * driver_for_each_device - Iterator for devices bound to a driver.
36 * @drv: Driver we're iterating.
37 * @start: Device to begin with
38 * @data: Data to pass to the callback.
39 * @fn: Function to call for each device.
40 *
41 * Iterate over the @drv's list of devices calling @fn for each one.
42 */
43int driver_for_each_device(struct device_driver *drv, struct device *start,
44 void *data, int (*fn)(struct device *, void *))
45{
46 struct klist_iter i;
47 struct device *dev;
48 int error = 0;
49
50 if (!drv)
51 return -EINVAL;
52
53 klist_iter_init_node(&drv->p->klist_devices, &i,
54 start ? &start->p->knode_driver : NULL);
55 while ((dev = next_device(&i)) && !error)
56 error = fn(dev, data);
57 klist_iter_exit(&i);
58 return error;
59}
60EXPORT_SYMBOL_GPL(driver_for_each_device);
61
62/**
63 * driver_find_device - device iterator for locating a particular device.
64 * @drv: The device's driver
65 * @start: Device to begin with
66 * @data: Data to pass to match function
67 * @match: Callback function to check device
68 *
69 * This is similar to the driver_for_each_device() function above, but
70 * it returns a reference to a device that is 'found' for later use, as
71 * determined by the @match callback.
72 *
73 * The callback should return 0 if the device doesn't match and non-zero
74 * if it does. If the callback returns non-zero, this function will
75 * return to the caller and not iterate over any more devices.
76 */
77struct device *driver_find_device(struct device_driver *drv,
78 struct device *start, void *data,
79 int (*match)(struct device *dev, void *data))
80{
81 struct klist_iter i;
82 struct device *dev;
83
84 if (!drv || !drv->p)
85 return NULL;
86
87 klist_iter_init_node(&drv->p->klist_devices, &i,
88 (start ? &start->p->knode_driver : NULL));
89 while ((dev = next_device(&i)))
90 if (match(dev, data) && get_device(dev))
91 break;
92 klist_iter_exit(&i);
93 return dev;
94}
95EXPORT_SYMBOL_GPL(driver_find_device);
96
97/**
98 * driver_create_file - create sysfs file for driver.
99 * @drv: driver.
100 * @attr: driver attribute descriptor.
101 */
102int driver_create_file(struct device_driver *drv,
103 const struct driver_attribute *attr)
104{
105 int error;
106
107 if (drv)
108 error = sysfs_create_file(&drv->p->kobj, &attr->attr);
109 else
110 error = -EINVAL;
111 return error;
112}
113EXPORT_SYMBOL_GPL(driver_create_file);
114
115/**
116 * driver_remove_file - remove sysfs file for driver.
117 * @drv: driver.
118 * @attr: driver attribute descriptor.
119 */
120void driver_remove_file(struct device_driver *drv,
121 const struct driver_attribute *attr)
122{
123 if (drv)
124 sysfs_remove_file(&drv->p->kobj, &attr->attr);
125}
126EXPORT_SYMBOL_GPL(driver_remove_file);
127
128int driver_add_groups(struct device_driver *drv,
129 const struct attribute_group **groups)
130{
131 return sysfs_create_groups(&drv->p->kobj, groups);
132}
133
134void driver_remove_groups(struct device_driver *drv,
135 const struct attribute_group **groups)
136{
137 sysfs_remove_groups(&drv->p->kobj, groups);
138}
139
140/**
141 * driver_register - register driver with bus
142 * @drv: driver to register
143 *
144 * We pass off most of the work to the bus_add_driver() call,
145 * since most of the things we have to do deal with the bus
146 * structures.
147 */
148int driver_register(struct device_driver *drv)
149{
150 int ret;
151 struct device_driver *other;
152
153 BUG_ON(!drv->bus->p);
154
155 if ((drv->bus->probe && drv->probe) ||
156 (drv->bus->remove && drv->remove) ||
157 (drv->bus->shutdown && drv->shutdown))
158 printk(KERN_WARNING "Driver '%s' needs updating - please use "
159 "bus_type methods\n", drv->name);
160
161 other = driver_find(drv->name, drv->bus);
162 if (other) {
163 printk(KERN_ERR "Error: Driver '%s' is already registered, "
164 "aborting...\n", drv->name);
165 return -EBUSY;
166 }
167
168 ret = bus_add_driver(drv);
169 if (ret)
170 return ret;
171 ret = driver_add_groups(drv, drv->groups);
172 if (ret) {
173 bus_remove_driver(drv);
174 return ret;
175 }
176 kobject_uevent(&drv->p->kobj, KOBJ_ADD);
177
178 return ret;
179}
180EXPORT_SYMBOL_GPL(driver_register);
181
182/**
183 * driver_unregister - remove driver from system.
184 * @drv: driver.
185 *
186 * Again, we pass off most of the work to the bus-level call.
187 */
188void driver_unregister(struct device_driver *drv)
189{
190 if (!drv || !drv->p) {
191 WARN(1, "Unexpected driver unregister!\n");
192 return;
193 }
194 driver_remove_groups(drv, drv->groups);
195 bus_remove_driver(drv);
196}
197EXPORT_SYMBOL_GPL(driver_unregister);
198
199/**
200 * driver_find - locate driver on a bus by its name.
201 * @name: name of the driver.
202 * @bus: bus to scan for the driver.
203 *
204 * Call kset_find_obj() to iterate over list of drivers on
205 * a bus to find driver by name. Return driver if found.
206 *
207 * This routine provides no locking to prevent the driver it returns
208 * from being unregistered or unloaded while the caller is using it.
209 * The caller is responsible for preventing this.
210 */
211struct device_driver *driver_find(const char *name, struct bus_type *bus)
212{
213 struct kobject *k = kset_find_obj(bus->p->drivers_kset, name);
214 struct driver_private *priv;
215
216 if (k) {
217 /* Drop reference added by kset_find_obj() */
218 kobject_put(k);
219 priv = to_driver(k);
220 return priv->driver;
221 }
222 return NULL;
223}
224EXPORT_SYMBOL_GPL(driver_find);